The invention described herein relates to a process for removal of the skins from tomatoes using thermophysical methods, and to a plant for its implementation. A process using thermophysical methods has already been in use on an industrial scale for some time; in such a process, the surface of the tomato is scalded by steam, whereupon the tomato itself is subjected to sudden depressurization. The sharp drop in pressure induces rapid formation of vapor under the skin of the tomato, the upshot of which is that the skin separates from the tomato pulp.
The process outlined above is implemented by conveying tomatoes into a pressure vessel; saturated steam is then directed into the vessel and brought thus into contact with the outer surface of the tomatoes. The tomatoes are generally drawn off from the vessel by way of a revolving gate valve.
Sudden depressurization in such a process is brought about conventionally by pumping cold water into one of the sectors of the revolving gate valve, thereby inducing rapid condensation of steam circulating in the space not occupied by the tomatoes, and occasioning a sharp drop in pressure.
Utilization of the process thus described is well justified by its marked simplicity and ease-of-operation; nonetheless, there are serious drawbacks. First and foremost, the introduction of water such as to make contact with the tomatoes signifies washing of the produce, resulting not only in a decline in quality of the end-product, but also in a loss of process efficiency. Second, the process calls for abundant supplies of water, which may not always be readily available in the warm season when tomatoes are processed. Third, and by no means of least importance, one is confronted with the difficulty of disposing of a large amount of liquid waste having a high content of organic matter; this implies complex and costly water treatment systems.
The main object of the invention is that of overcoming the drawbacks mentioned above, providing a process, and plant for its implementation, which will permit of stepping up both quality of the endproduct, and efficiency of the process; the quantity of water consumed in processing, moreover, is substantially reduced, and there is no waste requiring disposal.
An additional object of the invention is that of providing a process which will permit of reducing overall running costs without occasioning excessive increases in capital outlay on the installation of plant.
A marked advantage of the process is that it involves no installation of costly water treatment systems.